{"answers":{"affected":"It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-4221 exists.","fix":"No fix has been published for CVE-2021-4221 yet. Limit exposure of the affected software until one is available.","what":"CVE-2021-4221 is a medium-severity vulnerability in Mozilla Firefox, published on 22 Dec 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2021-4221 and fix it if it is affected.\n\nWhat it is: CVE-2021-4221 is a medium-severity vulnerability in Mozilla Firefox, published on 22 Dec 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-4221 exists.\n\nAffected product: Mozilla Firefox. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2021-4221/ (Markdown: https://insights.sbomify.com/CVE-2021-4221/index.md)","id":"CVE-2021-4221","markdown":"https://insights.sbomify.com/CVE-2021-4221/index.md","name":"CVE-2021-4221","record":{"aliases":["GHSA-wmph-fgw4-55rj"],"analysis":{"component_type":"browser","fix_type":"upgrade","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Firefox for Android","requires_auth":"none","summary":"RTL characters in domain names caused visual spoofing on Firefox for Android, enabling user confusion and potential phishing attacks.","user_interaction":"required","vuln_class":"other"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"mozilla","cpe":[{"product":"firefox","vendor":"mozilla"}],"cvss":{"score":4.3,"severity":"medium","source":"cisa-adp","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","version":"3.1"},"cwes":[{"id":"CWE-1007","name":"Insufficient Visual Distinction of Homoglyphs Presented to User"}],"description":"If a domain name contained a RTL character, it would cause the domain to be rendered to the right of the path. This could lead to user confusion and spoofing attacks. \u003cbr\u003e*This bug only affects Firefox for Android. Other operating systems are unaffected.*\u003cbr\u003e*Note*: Due to a clerical error this advisory was not included in the original announcement, and was added in Feburary 2022. This vulnerability affects Firefox \u003c 92.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":null,"headline":"Other in Firefox","id":"CVE-2021-4221","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"mozilla:firefox","products":["mozilla:firefox"],"type":"other","year":"2021"},"n_packages":0,"n_references":2,"next":{"headline":"WP Paginate \u003c 2.1.4 - Admin+ Stored Cross-Site Scripting","id":"CVE-2021-4222"},"packages":[],"prev":{"headline":"DO NOT USE THIS CANDIDATE NUMBER.","id":"CVE-2021-4220"},"products":["Firefox"],"published":"2022-12-22","related":[{"cvss_score":10,"headline":"Mozilla Firefox and Thunderbird Sandbox Escape","id":"CVE-2019-11708","kev_date_added":"2022-05-23","published":"2019-07-23"},{"cvss_score":9.8,"headline":"Mozilla Multiple Products Remote Code Execution","id":"CVE-2010-3765","kev_date_added":"2025-10-06","published":"2010-10-27"},{"cvss_score":9.6,"headline":"Mozilla Firefox Use-After-Free","id":"CVE-2022-26486","kev_date_added":"2022-03-07","published":"2022-12-22"},{"cvss_score":8.8,"headline":"Mozilla Firefox Use-After-Free","id":"CVE-2022-26485","kev_date_added":"2022-03-07","published":"2022-12-22"},{"cvss_score":8.8,"headline":"Mozilla Firefox and Thunderbird Type Confusion","id":"CVE-2019-11707","kev_date_added":"2022-05-23","published":"2019-07-23"},{"cvss_score":8.1,"headline":"Mozilla Firefox And Thunderbird Use-After-Free","id":"CVE-2020-6819","kev_date_added":"2021-11-03","published":"2020-04-24"},{"cvss_score":8.1,"headline":"Mozilla Firefox And Thunderbird Use-After-Free","id":"CVE-2020-6820","kev_date_added":"2021-11-03","published":"2020-04-24"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2025-04-16","vendors":["Mozilla"]},"summary":"RTL characters in domain names caused visual spoofing on Firefox for Android, enabling user confusion and potential phishing attacks.","url":"https://insights.sbomify.com/CVE-2021-4221/"}